Always use arc::InstanceHolder<T>::GetInstanceForMethod

chrome/browser/chromeos/arc/arc_auth_service.cc

Index: chrome/browser/chromeos/arc/arc_auth_service.cc
diff --git a/chrome/browser/chromeos/arc/arc_auth_service.cc b/chrome/browser/chromeos/arc/arc_auth_service.cc
index 2e8ad05bd143a9f806fc4a988984218bdba50906..4263d1468290b74e864aeb3b679020dd66141d83 100644
--- a/chrome/browser/chromeos/arc/arc_auth_service.cc
+++ b/chrome/browser/chromeos/arc/arc_auth_service.cc
@@ -229,8 +229,9 @@ bool ArcAuthService::IsAllowedForProfile(const Profile* profile) {
 }
 
 void ArcAuthService::OnInstanceReady() {
-  arc_bridge_service()->auth()->instance()->Init(
-      binding_.CreateInterfacePtrAndBind());
+  auto* instance = arc_bridge_service()->auth()->GetInstanceForMethod("Init");
+  CHECK(instance);

[dcheng, 2016/09/24 00:25:25]

We should prefer DCHECK() over CHECK() to document things that should "never
happen". CHECK() is for debugging things in crash reports or for preventing
security bugs, neither of which appears to be the case here.

[dcheng, 2016/09/24 00:27:13]

See
https://chromium.googlesource.com/chromium/src/+/master/styleguide/c++/c++.md...
for more information.

[Yusuke Sato, 2016/09/24 00:50:54]

Done.

[Yusuke Sato, 2016/09/24 00:50:54]

Acknowledged.

+  instance->Init(binding_.CreateInterfacePtrAndBind());
 }
 
 void ArcAuthService::OnBridgeStopped(ArcBridgeService::StopReason reason) {